Sigma-delta modulators are used in various technical fields. Analog/digital conversion (A/D conversion) by means of sigma-delta modulators is useful, e.g., in applications such as wireless or wire-connected communication systems, microcontrollers, sensors, audio/video conversion, etc. Such A/D converters (ADCs) provide a wide dynamic range in the conversion of input signals with a low to medium bandwidth. Based on their concept, the A/D conversion by means of sigma-delta modulators (sigma-delta conversion) provides for a high resolution and high linearity.
The principle of sigma/delta conversion is to measure, integrate and compensate for errors in the evaluation. The basic principles of sigma/delta conversion are known, e.g. from NORSWORTHY S. R., SCHREITER R., TEMES G. C. “Delta-Sigma Data Converters: Theory and Simulation”, IEEE Press, 2001.
Depending on the application, it may be worthwhile to reduce a noise contribution of the sigma-delta modulation, e.g. due to quantization noise. In this way, an ADC with a higher signal-to-noise ratio (SNR) can be obtained. For this purpose, higher-order sigma-delta modulators are used e.g., according to reference implementations. Higher-order sigma-delta modulators according to reference implementations have a number of analog amplification structures arranged in series or in parallel. Such an amplification structure can be designed, e.g., as integrator.
However, such techniques can have certain disadvantages and restrictions. E.g., higher-order sigma-delta modulators can have instabilities. This may reduce the accuracy and/or the maximum usable dynamic range of the A/D conversion.